<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        class Father {
            say () {
                return '我是爸爸';
            }
        }
        class Son extends Father {
            say () {
                console.log(`${super.say()}的儿子`);
            }
        }
        const son = new Son();
        son.say();
    </script>
</body>
</html>